1. Field of the Invention
The present invention relates to a cassette loading device of the front loading type for loading a cassette with a magnetic tape wound on two reels therein, into a video cassette recorder (VCR).
2. Prior Art
Certain cassette loading devices of the front loading type for use in VCRs are constructed such that they can selectively loading standard cassettes and smaller cassettes into the VCRs.
Known cassette loading devices of the above type include a cassette holder for holding a cassette and loading the cassette into a loaded position. The cassette holder has a width which is substantially the same as the width of the standard cassette. Therefore, without some cassette positioning mechanism, the smaller cassette might be placed anywhere in the cassette holder and might not be inserted as desired in a predetermined proper position in the cassette holder.
Japanese Laid-Open Patent Publications Nos. 63(1988)-146263 and 63(1988)-191347, for example, disclose cassette loading devices which can insert a smaller cassette in a predetermined proper position in such a cassette holder.
The cassette loading device shown in the former publication includes two cassette detectors positioned respectively at locations spaced from each other by a distance which is substantially the same as the width of the smaller cassette, two lock members also positioned at those locations, respectively, and actuatable in ganged relation to the cassette detectors, and a cassette insertion prevention lid disposed substantially centrally between the cassette detectors. These detectors, lock members, and cassette prevention lid are positioned in a cassette insertion slot. When a smaller cassette is inserted in a proper position through the cassette insertion slot, the cassette detectors and lock members are operated to open the cassette insertion prevention lid, thereby allowing the smaller cassette to be loaded in position. When the smaller cassette is inserted in a wrong position, only one cassette detector is actuated, and the other cassette detector and lock member remain inactivated, keeping the cassette insertion prevention lid closed.
However, the cassette detectors, the lock members, and the cassette insertion prevention lid are complex in structure, increase the number of parts used, and make the cassette loading device costly to manufacture. The disclosed cassette loading mechanism is located on an upper panel of the cassette holder, so that the overall thickness or vertical dimension of the cassette loading device is relatively large, and so is the VCR in which the cassette loading device is incorporated.
The cassette loading device disclosed in the latter publication has two horizontally divided doors which normally cover a cassette insertion slot. One of the doors, for example, the left door, has a width corresponding to the width of the smaller cassette. The doors are associated with respective door lock levers. A smaller cassette can be inserted into the cassette holder while opening the left door, and a standard cassette can be inserted into the cassette holder while opening both the left and right doors. The smaller and standard cassettes, which are alternatively loaded in position, have their left and front end surfaces positioned in alignment with a common plane. The disclosed cassette loading device is designed for loading cassettes for professional use, known as MII-format VCR cassettes.
The door lock levers are disposed in a low position. Since a smaller cassette is pushed upwardly by the door lock members, it has to be inserted with horizontal forces as well as downward forces applied thereto. Consequently, it is relatively difficult to insert the smaller cassette into the VCR.
A smaller cassette for consumer use, typically referred to as VHS-C (registered trademark) cassette, is narrower than such a smaller cassette for professional use. Therefore, a smaller cassette for consumer use cannot be inserted in a proper position by the disclosed cassette loading device.
One solution is to employ a smaller door corresponding to a consumer-use smaller cassette, the smaller door being pivotally mounted on a larger door and displaced inwardly, i.e., spaced a certain distance from the left end of the larger door. Since the smaller door is spaced from the left end of the larger door, the left lock lever associated with the smaller door is also displaced inwardly, i.e., spaced from the left end of the larger door. However, when a standard cassette is inserted and ejected through the larger door, the left lock lever which is displaced inwardly tends to project into an opening in the bottom of the standard cassette, which opening serves to receive a tape loading member in the VCR. The lock lever thus projecting into the opening in the cassette bottom is liable to damage the magnetic tape in the standard cassette.
The above construction is also incorporated in a VCR which employs a standard cassette known as a VHS (registered trademark) cassette for consumer use and a smaller cassette or a VHS-C cassette for consumer use. When a cassette is loaded in such a VCR, the doors are closed and locked by the door lock levers. In order to eject the loaded cassette, the door lock levers must be turned into an unlocking position by solenoids or the like. Because of the solenoids used, the number of parts required is relatively large, the VCR itself is expensive to manufacture, and the sequence of controlling the cassette loading device is complex.
When a loaded cassette is to be ejected, the doors are turned into an open position by levers. Heretofore, both doors are turned when a standard cassette is ejected or a smaller cassette is ejected. Therefore, the right door, which has nothing to do with the smaller cassette, is also turned, when the smaller cassette is ejected. Upon reinsertion of the ejected smaller cassette, the smaller cassette may be laterally displaced as it is not limited in lateral position by the right door. The laterally displaced smaller cassette cannot however be inserted properly into the VCR. The right door which is turned into its open position when the smaller cassette is ejected also allows entry of foreign matter into the VCR.
Japanese Laid-Open Patent Publication No. 63(1988)-55754 discloses a cassette loading device which can insert a smaller cassette into a predetermined normal position in a VCR. The disclosed cassette loading device has a guide for guiding a smaller cassette which is inserted through a corresponding door. The guide is movable in ganged relation to a lever which is angularly moved when pushed by a standard cassette which is inserted through a corresponding door. When the standard cassette is inserted, the guide is moved out of the path of the standard cassette in ganged relation to the lever.
The above cassette loading device requires the special guide for guiding smaller cassettes. The door for smaller cassettes is freely angularly movable when no smaller cassette is inserted. Therefore, a smaller cassette may erroneously longitudinally be inserted through the door, or foreign matter may be inserted through the door.